Lake Averno sediment was used to isolate the facultative anaerobic bacteria having the potential for H2 production. Twenty-Wve out of 35 isolates recovered from the sediment sample produced hydrogen under anaerobic conditions from glucose with yields ranging from 0.1 to 0.49 mol H2/mol glucose. IdentiWcation based on 16S rRNA gene sequence analysis revealed that most of them belong to the Firmicutes group, with a prevalence of the Paenibacillus polymyxa species. Seven distinct genomic Wngerprints among the 11 P. polymyxa isolates were obtained using the random ampliWed polymorphic DNA (RAPD) technique. Glucose fermentation by P. polymyxa isolates was investigated. Glucose was totally consumed after 3 days of fermentation. The fermentation products were hydrogen (0.18-0.47 mol H2/mol glucose), ethanol (0.1-0.5 mol ethanol/mol glucose), and 2,3-butanediol (0.1 mol 2,3-butanediol/mol glucose). Lower amounts of acetic, butyric, formic, lactic, and propionic acids were detected. All metabolic data concerning P. polymyxa isolates were analyzed by cluster analysis to reveal similarities and/or diVerences with clustering based on RAPD proWles. Despite the high metabolic similarity among almost all P. paenibacillus isolates, results of cluster analyses of metabolic and genetic data do not match completely. © 2011 Springer-Verlag.

Export Date: 12 July 2012Source: Scopus